How Does Machine Espresso Work?

Machine espresso uses precision pressure and mind-blowing filter technology to create the delicious coffee we enjoy. What exactly does it work?

Espresso is produced by pushing hot water at high pressure through finely-ground coffee. The process is similar to making drip coffee, but the difference is in the pressure.

The Group Head

As the name suggests the group head is the place you put your portafilter in when brewing espresso. It disperses water into the portafilter, and then regulates the pressure of extraction. There are a variety of group heads each with distinct advantages and disadvantages. Some are specifically designed for stability of temperature while others are designed to handle pre-infusion. Others are made to control the lever. Some have a combination, like the E61. This is a favorite among baristas because it offers multiple advantages in one package.

As you can see from the image above the head of the group is fitted with a variety of notches. You can place your portafilter in these notches, then turn the head around to secure it. There is also a gasket made of rubber in the notches and helps to create the seal when you insert your portafilter into the machine. The notches allow for precise placement of your portafilter. This is essential for an accurate extraction.

The group head is not just able to allow you to put in your portafilter easily however, it also keeps a constant temperature. This is accomplished by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is at the right level to extract the coffee. This is crucial, since just a few degrees could make the difference between excellent and great espresso.

The Pump

The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bars of pressure required to extract espresso. This is different from manual piston machines that rely on a lever. The pressure builds up by removing tap water from a reservoir and pumping it through a heat exchanger prior being shot through the ground coffee in the group head.

Pumps are generally less expensive and last for longer than piston-driven machines. However, both types of machines may degrade because of frequent use and poor cleaning. They also create mechanical complexity which can result in a high price tag on even the most basic models.

Some espresso and filter coffee machine machines employ steam pressure instead of a pump for brewing espresso. The disadvantage of this is that the same boiler that produces steam also increases the temperature of the water until it reaches boiling which can cause over-extraction. They also have to continuously rebuild their pressure between cups. This takes energy and time.

A majority of espresso coffee machines for sale machines utilize an rotary or a vibration pump. A vibration model makes use of the vibrating disk to create pressure, while the circular model pushes hot liquid through the ground at a high speed. Both types of machines can make a great espresso, however Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the element that heats the water to the optimal temperature to extract. The steam that is created is then directed to the portafilter, which holds the home espresso machine grounds. It is then funneled into the cup. The steam generates enough pressure to push the grounds of the coffee through. This creates a crema on top of the retro espresso machine. This is one of the hallmarks of a good espresso.

There are three kinds of espresso machines, each with a different type of pump and the temperature of the brew. There are various ways that the brew can be controlled, as well as the size of the cup the machine can make.

The first espresso machines were steam-type. The first espresso machines were steam-type machines. The coffee tasted bitter and burned. The modern espresso machine was invented by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semi-automatic machine with an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine, you have to grind the beans and tamp them yourself but the pump provides regulated water flow and pressure. This is an excellent compromise between human touch and the mechanized quality.

The Filter

Espresso machines usually use a filter that separates the grounds of the coffee from the hot water. The filter is also an essential component of the machine's temperature control, since it stops overheating.

It also helps with flavor as a filter can allow for a longer bloom time. This allows the beans to release their flavor and allows for better extraction.

However it is crucial to keep in mind that even a high-quality filter could result in a bad cup of coffee, since the quality of the beans and extraction is important.

It's here that the magic takes place. This is what makes espresso taste so good. The grouphead (also called the brewhead) is where you place the portafilter - the thingy that you put the coffee grounds into, when making espresso.

Steam-driven espresso machine coffee machines use hot water that is heated inside an airtight vessel to create steam. The steam then moves hot water through the grounds of coffee under high pressure. These kinds of machines are typically less expensive and easier to maintain than pumps-driven models. They are however limited in their ability to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, compressed-air-pump-driven espresso machines have become more popular. They utilize an air compressor to push hot water through the grounds and are significantly more portable than steam-driven electric machines.